1. Technical Field
The invention relates generally to a hopper door assembly and method for feeding bulk metal objects from a hopper. More particularly, the invention relates to a hopper door assembly and method for feeding railroad spikes from a hopper onto a conveyor belt, which in turn feeds an automated spike driver. Specifically, the invention relates to a hopper door assembly with hopper doors having arms extending into the hopper which engage the spikes to assist moving and feeding them through the open doors.
2. Background Information
In the railway industry, machines for automatically driving railroad spikes in the laying of track are now commonplace. Also known are hopper and conveyor belt combinations which work in conjunction with such machines to feed those machines with railroad spikes. The present invention relates to an improved hopper door assembly and method for feeding the railroad spikes from the hopper onto the conveyor belt of such combinations.
One of the problems with the feeding of the spikes is their lack of a simple flow pattern. The spikes tend to interlock to some degree, due to their shape, and thus do not flow easily down the tapered side panels of the hopper so that they can be controllably released through an opening at the bottom of the hopper. The weight of the spikes also affects this lack of a simple flow pattern. A further factor adding to this problem is the friction between the spikes themselves and between the spikes and the side panels of the hopper, due to metal composition, shape and surface texture of the spikes. The art thus desires a hopper door assembly that allows or encourages the spikes to effectively move or flow through the outlet of a hopper.
The prior art does not address the flow problem created by the interlocking nature of the railroad spikes and other factors noted above. Previously, a substantially horizontal door was disposed at the bottom of the hopper, the door sliding horizontally between open and closed positions to respectively release and prevent release of the spikes. While this design is presumably adequate for the purpose for which it was intended, it does not address other issues present in the art.
The invention provides doors for hopper with arms that project into the hopper to help move items through the lower opening of the hopper.
The invention also provides hopper doors that are heavy so that vibrational forces may be created by opening and closing the doors.
The invention also provides piston and cylinder combinations with sufficient force to create vibrations when opening and closing the doors.
The invention provides a door assembly for feeding bulk items from a hopper which has sidewalls that define a lower opening. The door assembly includes first and second opposed doors pivotally connected to the sidewalls, the doors being movable between open and closed positions. The lower opening is closed when the doors are closed and open when the doors are open. At least one arm is connected to at least one of the doors. The at least one arm extends into the hopper when the doors are closed.
The invention also provides a method for feeding bulk items from a hopper comprising the steps of providing a door assembly for feeding bulk items from a hopper; providing items in bulk; placing at least some of the items in the hopper; and opening the doors at least partially to release at least one of the items through the lower opening.